The endometrium consists of two layers, functional and basal. Which layer sheds with menses?

The endometrium consists of two layers, functional and basal. Which layer sheds with menses?

• A. Basal
• B. Functional
• C. Endometrium
• D. Myometrium

Answer: (B)

The endometrium has a superficial functional layer that responds to the monthly hormonal cycle and a deeper basal layer that remains after shedding. During the cycle, the functional layer thickens and becomes highly vascularized in preparation for possible implantation. If pregnancy does not occur, withdrawal of progesterone causes the functional layer to shed, resulting in menses. The basal layer remains intact and serves as the source to regenerate a new functional layer in the next cycle. The myometrium, the muscular layer surrounding the endometrium, is not shed. So the layer that is shed during menses is the functional layer.

The endometrium has a superficial functional layer that responds to the monthly hormonal cycle and a deeper basal layer that remains after shedding. During the cycle, the functional layer thickens and becomes highly vascularized in preparation for possible implantation. If pregnancy does not occur, withdrawal of progesterone causes the functional layer to shed, resulting in menses. The basal layer remains intact and serves as the source to regenerate a new functional layer in the next cycle. The myometrium, the muscular layer surrounding the endometrium, is not shed. So the layer that is shed during menses is the functional layer.